Left heart decompression in patients supported with extracorporeal membrane oxygenation for cardiac disease

Patients on extracorporeal membrane oxygenation (ECMO) for cardiac disease frequently have some degree of left ventricular (LV) distension due to incomplete unloading. However, a chronically or excessively volume overloaded and distended LV, with persistently elevated left ventricular end-diastolic pressure (LVEDP) and elevated wall stress, impairs myocardial recovery and the ability to wean off ECMO. The presence of concomitant cardiogenic pulmonary edema, in many cases, also leads to poor patient outcomes. Thus, in order to unload and decompress the left heart, conservative, pharmacologic, interventional and surgical strategies have been described [1, 2].
In this issue, the authors present the use of transseptal balloon atrial septostomy (BAS) and balloon dilation, to vent the left heart, in an adult patient with dilated cardiomyopathy and severe biventricular failure on ECMO, with worsening pulmonary edema. While treatment strategies have been reviewed, the timing, indications and algorithm for left heart decompression for patients on ECMO, especially by percutaneous BAS, remain debatable. Actual treatment strategies remain customized and decided on a case-by-case basis.
With regards to the timing for left heart decompression for patients on ECMO, in one single-center case series (23 pediatric patients), it appears that earlier LA decompression (by all modalities) is associated with better LV recovery and improved likelihood of weaning from ECMO [3]. In another single-center case series (37 pediatric patients), trans-catheter procedures to decompress the left heart were performed in 97% of patients within 24 h of ECMO initiation [4]. In a multi-center case series (64 patients: 32 adult, 32 pediatric) and the only study to include adult patients with available data on timing of intervention, Baruteau et al. [5] report that the mean ECMO-BAS timing was 1.5 days, with a range of 0 to 12 days. In a literature summary by the same authors, previously reported mean ECMO-BAS timings for pediatric patients ranged from 8 h to 2.5 days.
A review of the literature found the following indications for left heart decompression [1–10]:
1. Hearts with no obvious ejection and a closed aortic valve (as in the patient discussed in this issue),
2. Refractory pulmonary edema (as in the patient discussed in this issue),
3. Distended left atrium (LA) and LV with elevated LA pressure and LVEDP, despite maximal pharmacologic support,
4....


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